JP2022182535A - Battery control device and battery control method - Google Patents

Abstract

To reduce a processing load required for estimating deterioration of a battery.SOLUTION: A battery control device according to an embodiment includes: a whole number estimation part; a setting part; and a priority estimation part. The whole number estimation part estimates a deterioration degree for each of blocks in a battery cell contained in a battery pack mounted on a vehicle when a first event occurs. The setting part sets a priority to each block on the basis of an estimation result by the whole number estimation part. The priority estimation part estimates the deterioration degree of each block of the blocks that the priority set by the setting part satisfies a predetermined condition when a second event occurs.SELECTED DRAWING: Figure 2

Description

The present invention relates to a battery control device and a battery control method.

Conventionally, deterioration estimation of a battery has been performed for the purpose of suggesting when to replace the secondary battery. Degradation of a secondary battery refers to a state such as a decrease in capacity and an increase in internal resistance of the battery. The degree of deterioration of the secondary battery is estimated from the correlation of battery parameters such as voltage value, current value and temperature.

A secondary battery mounted on an automobile is formed by connecting battery cell blocks to form one battery pack. In addition, the battery pack is controlled so as not to over-discharge and over-charge according to the most deteriorated battery cell block.

Therefore, in the conventional degradation estimation, the degradation levels of all battery cell blocks included in the battery pack are estimated in order to grasp the battery cell block with the highest degradation level.

JP 2019-185953 A

However, the conventional technology has a problem that the processing load required for estimating deterioration of the battery is large.

For example, when performing the aforementioned over-discharging and over-charging controls, it is necessary to periodically perform deterioration estimation for all battery cell blocks.

Since degradation estimation may be performed in real time while the vehicle is running, available time and computer resources are limited.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery control device and a battery control method capable of reducing the processing load required for estimating deterioration of a battery.

In order to solve the above-described problems and achieve the object, the battery control device according to the present invention has a first estimating section, a setting section, and a second estimating section. The first estimation unit estimates the degree of deterioration of each of the battery cell blocks included in the battery pack mounted on the vehicle when the first event occurs. The setting unit sets priority to each block based on the estimation result by the first estimation unit. The second estimating unit estimates the degree of deterioration of each of the blocks whose priority set by the setting unit satisfies a predetermined condition when the second event occurs.

According to the present invention, it is possible to reduce the processing load required for battery deterioration estimation.

FIG. 1 is a diagram showing a configuration example of a battery pack. FIG. 2 is a diagram illustrating a configuration example of the battery control device according to the embodiment. FIG. 3 is a diagram for explaining deterioration estimation. FIG. 4 is a diagram illustrating an example of a priority setting method. FIG. 5 is a diagram for explaining variations in the degree of deterioration. FIG. 6 is a diagram showing an example of a priority setting table. FIG. 7 is a diagram showing an example of a priority setting table. FIG. 8 is a diagram showing an example of a priority setting table. FIG. 9 is a diagram showing an example of a priority setting table. FIG. 10 is a flowchart illustrating the procedure of processing executed by the battery control device according to the embodiment.

Hereinafter, embodiments of a battery control device and a battery control method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

First, the battery pack will be described with reference to FIG. FIG. 1 is a diagram showing a configuration example of a battery pack.

As shown in FIG. 1, a battery pack 1P is formed by connecting a plurality of battery cell blocks in series or in parallel. Reference numerals 1b to 14b in FIG. 1 represent battery cell blocks. The battery pack 1P is mounted on a vehicle, for example.

A battery cell block may be composed of one battery cell, or may be composed of a plurality of battery cells.

It is also assumed that voltage, temperature, and the like can be acquired as sensor values from each battery cell block. A battery cell block is an example of a unit for estimating the degree of deterioration.

A battery control device according to an embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating a configuration example of the battery control device according to the embodiment.

The battery control device 10 shown in FIG. 2 may be realized, for example, by an ECU (Electronic Control Unit) mounted on a vehicle.

The battery control device 10 estimates deterioration of the battery pack 1P. The deterioration estimation result may be used for charging and discharging control, or may be used for vehicle maintenance such as battery pack replacement.

As shown in FIG. 2 , the battery control device 10 has an interface section 11 , a storage section 12 and a control section 13 .

The interface unit 11 is an interface for connecting the battery control device 10 with other devices.

The storage unit 12 and the control unit 13 of the battery control device 10 are, for example, a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, an input/output port, etc. realized by a circuit. Moreover, the memory|storage part 12 and the control part 13 of the battery control apparatus 10 may be implement|achieved by ECU.

The CPU of the computer functions as a total estimation unit 131, a setting unit 132, and a priority estimation unit 133 of the control unit 13 by reading and executing programs stored in the ROM, for example.

Also, the storage unit 12 corresponds to a RAM or a flash memory. The RAM and flash memory can store the estimation result information 121, the setting information 122, various program information, and the like.

Note that the battery control device 10 may acquire the above-described programs and various information via another computer or a portable recording medium connected via a wired or wireless network.

Deterioration estimation performed by each processing unit of the control unit 13 will be described with reference to FIG. FIG. 3 is a diagram for explaining deterioration estimation.

First, when the first event occurs, the total number estimation unit 131 estimates the degree of deterioration of each block of battery cells included in the battery pack 1P mounted on the vehicle.

In the following description, a block of battery cells may be simply referred to as a block.

Here, the first event is starting or stopping of the vehicle, starting charging/discharging of the battery pack 1P, continuing or stopping for a certain period of time, or the like.

Furthermore, regardless of the state of the vehicle and the battery pack 1P, it may be considered that the first event has occurred each time a predetermined period of time (for example, one minute) elapses.

The total number estimator 131, which is the first estimator, estimates (calculates) the degree of deterioration for all battery cell blocks included in the battery pack 1P. For example, the total number estimator 131 calculates the degree of deterioration of the battery cell blocks from block 1b to block 14b.

The setting unit 132 sets priority to each block based on the estimation result by the total number estimation unit 131 .

The priority estimator 133, which is the second estimator, determines the degree of deterioration of each of the blocks whose priority set by the setting unit 132 satisfies a predetermined condition when the second event occurs. Estimate (calculate). For example, the priority estimator 133 calculates the degree of deterioration of block 2b among the battery cell blocks from block 1b to block 14b.

In this way, the priority estimation unit 133 reduces the processing load by estimating the degree of deterioration of some blocks instead of all blocks.

The priority estimator 133 can use the calculation result of the total estimator 131 for blocks for which the degree of deterioration is not calculated.

Further, the calculation of the degree of deterioration by the total estimation unit 131 and the priority estimation unit 133 may be performed by any method. Note that the total number estimation unit 131 and the priority estimation unit 133 differ in the blocks to be estimated, but the method of calculating the degree of deterioration for each block is common.

For example, the total estimator 131 and the priority estimator 133 can obtain the degree of deterioration by inputting sensor values such as voltage and temperature acquired from each block into a trained neural network.

For example, the total estimating unit 131 and the priority estimating unit 133 may calculate the degree of deterioration based on the sensor values obtained when performing each estimation, or if an increase in the amount of calculation is allowed, the previous You may calculate a deterioration degree using the result obtained by estimation.

Further, for example, the total estimation unit 131 and the priority estimation unit 133 may calculate the degree of deterioration using a predetermined regression equation or the like without using the machine learning technique.

Note that the total estimation unit 131 and the priority estimation unit 133 may calculate the degree of deterioration by different methods. For example, the total number estimating unit 131 performs calculations using a high-precision method with a large amount of calculation, and the priority estimating unit 133 calculates the degree of deterioration with a simple method with a small amount of calculations.

Also, the priority estimation unit 133 estimates the degree of deterioration when the second event occurs. The second event may be the same as or different from the first event.

Here, it is assumed that each time a predetermined event relating to the first event and the second event occurs, the number of times is counted.

Assuming that the number of occurrences of an event is i, the battery control device 10 considers that the first event has occurred when the event occurs and the number of times i satisfies the first condition. Also, when an event occurs and the number of times i satisfies the second condition, the battery control device 10 considers that the first event has occurred.

For example, the first condition is that the remainder of i divided by 10 is 1 or 2. Also, for example, the second condition is that the remainder when i is divided by 10 is neither 1 nor 2.

In this case, when i is 1, 2, 11, 12, etc., the total estimation unit 131 estimates the degree of deterioration. On the other hand, when i is 3, 4, 5, 6, 7, 8, 9, 10, etc., the priority estimation unit 133 estimates the degree of deterioration.

For example, assume that i in FIG. 3 is 3. At this time, the priority estimation unit 133 performs the same estimation processing as the i-th (third) time from the fourth time to the tenth time.

The setting unit 132 sets a higher priority to a block with a higher degree of deterioration estimated by the total number estimation unit 131 .

This makes it possible to obtain detailed information about blocks that are more degraded.

The total number estimator 131 may estimate the degree of deterioration twice or more for each block of battery cells. In the example of FIG. 3, the total estimation unit 131 estimates the degree of deterioration twice.

At this time, the setting unit 132 sets the priority based on two or more estimation results by the total estimation unit 131 .

In this way, by using the results of the exhaustive estimation performed multiple times, it is possible to set more effective priorities.

A priority setting method will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of a priority setting method.

It is assumed that the three tables shown in FIG. 4 are stored in the storage unit 12 as the estimation result information 121. FIG.

First, it is assumed that the total estimation unit 131 has obtained the (i−2)-th estimation result. For example, the degree of deterioration of block 1c is "small" and the degree of deterioration of block 1b is "large" at the (i-2)th time.

However, the degree of deterioration "large" means that the deterioration is greater than that of the degree of deterioration "small". The degree of deterioration "middle" is between "large" and "small". Further, the notation method of the degree of deterioration is not limited to that shown in FIG.

The "target block" in FIG. 4 is a block with a high priority. The setting unit 132 does not set the priority from the (i−2)th estimation result.

The setting unit 132 sets the priority used in the i-th deterioration estimation based on the i−2th estimation result and the i−1th estimation result.

First, the setting unit 132 identifies a block with the highest degree of deterioration. For example, in the case of FIG. 4, the setting unit 132 specifies that the block 2b having the degree of deterioration of "high" at the i−2 and i−1 times is the block with the highest degree of deterioration.

Here, the setting unit 132 selects, for each block, the highest estimated value obtained from the total number of estimations (for example, the i-2th and i-1th times in FIG. 4), and selects the selected A block with the highest degree of deterioration may be identified based on the estimated value.

In addition, the setting unit 132, based on the average value for each block of the estimated values obtained in a plurality of total estimation (for example, i-2 and i-1 in FIG. 4), the block with the highest degree of deterioration may be specified.

In addition, the setting unit 132 identifies blocks with a large degree of deterioration variation. For example, the setting unit 132 identifies the block 1b whose degree of deterioration has changed from "low" to "medium" at the i-2nd and i-2nd times. In this example, the difference in the degree of deterioration is one step between "low" and "medium", but the larger the difference, such as two steps, the greater the variation.

Then, the setting unit 132 sets high priority to the identified blocks 1b and 2b.

In this way, the setting unit 132 sets a higher priority to a block with a larger variation in the degree of deterioration estimated by the total number estimation unit 131 .

In this way, by taking into consideration not only the simple degree of deterioration, but also variations, it is possible to specify a block or the like that has suddenly deteriorated, and to set a more meaningful priority.

In the example of FIG. 4 , the setting unit 132 selects one each of the block with the largest degree of deterioration and the block with the largest variation, and designates them as the estimation target block of the priority estimation unit 133 .

On the other hand, the setting unit 132 may select multiple blocks for each of the degree of deterioration and variation.

For example, the setting unit 132 may select all blocks whose degree of deterioration and degree of variation are equal to or greater than a predetermined standard, or may select a predetermined number of blocks from blocks with a higher degree of deterioration and degree of variation. good too.

Furthermore, the blocks to be estimated by the priority estimation unit 133 may not be changed until the next estimation by the total number estimation unit 131 is performed. On the other hand, a block whose degree of deterioration or degree of variation has become low during a plurality of times of estimation by the priority estimation unit 133 may be excluded from estimation targets.

For example, in the example of FIG. 4, the block 1b is excluded from the estimation target of the priority estimation unit 133 at the (i+1)th time.

Note that the number of times the total estimation unit 131 estimates the degree of deterioration does not have to be continuous.

For example, when i is a multiple of 5 such as 5 or 10 (for example, the 5th time or the 10th time), the total estimation unit 131 estimates the degree of deterioration. Then, the setting unit 132 sets the priority based on the deterioration level estimation result at that time.

For example, the setting unit 132 may set the priority of deterioration estimation by the priority estimating unit 133 after that (for example, the 6th to 9th times) based on the result of one estimation (for example, the result of the 5th time). good.

Further, for example, the setting unit 132, based on a plurality of estimation results (eg, the larger one or the average value of the degree of deterioration estimated in the first and fifth times), after that (for example, the sixth to ninth) priority The priority of deterioration estimation by the estimation unit 133 may be set.

In this case, the setting unit 132 can determine a block with a large variation using the estimation results of the total number estimation unit 131 for a plurality of times (for example, the fifth and tenth results) with the closest measurement timings.

Furthermore, when i is 11, 12, 13, 14, etc., the priority estimation unit 133 estimates the degree of deterioration based on the priority.

[Method of setting priority using the priority table]
Furthermore, the setting unit 132 can set a predetermined priority according to the degree of deterioration estimated by the total number estimation unit 131 and the variation for each block.

This allows efficient rule-based prioritization.

First, the setting unit 132 determines the maximum value and variation of the degree of deterioration as shown in FIG. FIG. 5 is a diagram for explaining variations in the degree of deterioration.

The setting unit 132 sets (1) to the maximum deterioration level estimated in the i−2-th and i−1-th deterioration level estimations.

Further, the setting unit 132 classifies the variation in the degree of deterioration estimated in the i-2nd and i-1st deterioration degree estimations into one of "A", "B", and "C" ( 2).

“A” means that the degree of deterioration did not change between the i−2 times and the i−1 times. For example, block 2b is classified as "A" because the degree of deterioration remains "large" both in the i-2 and i-1 times.

"B" indicates that the degree of deterioration has changed by one step between the i-2nd and i-1st times, that is, between "small" and "medium", or between "medium" and "large". means. For example, block 1b is classified as "B" because the degree of deterioration changes from "low" to "medium".

"C" means that the degree of deterioration has changed in two stages between the i-2nd time and the i-1th time, that is, the change has occurred between "small" and "large". For example, block 3b is classified as "C" because the degree of deterioration changes from "large" to "small".

Here, the setting unit 132 sets the priority by combining (1) and (2). At this time, the setting unit 132 uses the priority setting table stored in the storage unit 12 as the setting information 122 .

The priority in the priority setting table means the order of priority, and the smaller the number, the higher the priority.

Also, the priority setting table may be created in advance by an administrator or the like.

FIG. 6 is a diagram showing an example of a priority setting table. The priority setting table of FIG. 6 is used when the degree of deterioration of the most deteriorated block is "large".

For example, according to the priority setting table of FIG. 6, the setting unit 132 sets the priority of a block whose (1) is "high" and whose (2) is "A" to "1".

FIG. 7 is a diagram showing an example of a priority setting table. The priority setting table in FIG. 7 is used when the degree of deterioration of the most deteriorated block is "medium".

For example, according to the priority setting table of FIG. 7, the setting unit 132 sets the priority of a block having (1) "middle" and (2) "A" to "1".

FIG. 8 is a diagram showing an example of a priority setting table. The priority setting table of FIG. 8 is used when the degree of deterioration of the most degraded block is "small".

For example, according to the priority setting table of FIG. 8, the setting unit 132 sets the priority of a block having (1) "middle" and (2) "B" to "1".

FIG. 9 is a diagram showing an example of a priority setting table. The priority setting table of FIG. 9 is used when the degree of deterioration of the most deteriorated block cannot be specified.

For example, according to the priority setting table of FIG. 9, the setting unit 132 sets the priority of a block whose (1) is "middle" and whose (2) is "B" to "1".

Note that, if there are a plurality of blocks with the same priority, the priority estimation unit 133 may estimate the degree of deterioration only for the number of blocks determined by tuning in advance.

For example, in the priority setting tables shown in FIGS. 6 to 9, priorities may be set according to rules 1 and 2 below.
Rule 1: If the degree of deterioration is the same, a higher priority is set for the one with the greater variation.
Rule 2: Regardless of rule 1, when the degree of deterioration is the highest (for example, (1) is "large"), the highest priority is set to those with no variation.

For example, according to Rule 2, the highest priority "1" is set for a block shown in FIG. 6 where (1) is "high" and (2) is "A".

On the other hand, according to Rule 1, a higher priority is set for a block with (1) of "medium" shown in FIG.

As a result, in the priority table of FIG. The order of priority is reversed.

A procedure of processing executed in the battery control device 10 according to the embodiment will be described with reference to FIG. 10 . FIG. 10 is a flowchart illustrating the procedure of processing executed by the battery control device according to the embodiment.

As shown in FIG. 8, first, the battery control device 10 sets i to 1 (step S101).

Then, the battery control device 10 detects occurrence of an event (step S102). Events include the start or stop of running with the battery pack mounted, the start or end of charging/discharging of the battery pack, the start of energization of a predetermined in-vehicle device, the elapse of a certain period of time, and the like.

Here, the battery control device 10 determines whether or not i satisfies the conditions for total estimation (step S103). The condition for exhaustive estimation is that the remainder when i is divided by 10 is 1 or 2, for example.

Then, when i satisfies the condition for all estimation (step S103, Yes), the battery control device 10 estimates the degree of deterioration of all battery cell blocks (step S104).

On the other hand, if i does not satisfy the conditions for 100% estimation (step S103, No), the battery control device 10 estimates the degree of deterioration of the battery cell blocks whose priority is equal to or higher than the predetermined value (step S105).

Subsequently, the battery control device 10 sets a priority to each battery cell block based on the deterioration degree estimation result (step S106).

Here, when the estimation process is terminated (step S107, Yes), the battery control device 10 terminates the process.

On the other hand, if the estimation process is not finished (step S107, No), the battery control device 10 increases i by 1 (step S108), returns to step S102, and repeats the process.

As described above, the battery control device 10 according to the embodiment has the total number estimating section 131 , the setting section 132 and the priority estimating section 133 . Total estimation unit 131 estimates the degree of deterioration of each block of battery cells included in battery pack 1P mounted on the vehicle when the first event occurs. The setting unit 132 sets priority to each block based on the estimation result by the total number estimation unit 131 . The priority estimator 133 estimates the degree of deterioration of each of the blocks whose priority set by the setter 132 satisfies a predetermined condition when the second event occurs.

In this way, the battery control device 10 can perform deterioration degree estimation for some battery cell blocks according to the priority instead of constantly estimating the degree of deterioration for all battery cell blocks. As a result, according to the present embodiment, it is possible to reduce the processing load required for battery deterioration estimation.

Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

1P Battery pack 1b, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b, 10b, 11b, 12b, 13b, 14b Block 10 Battery control device 11 Interface unit 12 Storage unit 13 Control unit 121 Estimation result information 122 Setting Information 131 Total estimation unit 132 Setting unit 133 Priority estimation unit

Claims (6)

a first estimation unit for estimating the degree of deterioration of each block of battery cells included in a battery pack mounted on a vehicle when a first event occurs;
a setting unit that sets a priority to each of the blocks based on the estimation result of the first estimation unit;
a second estimating unit for estimating the degree of deterioration of each of the blocks whose priority set by the setting unit satisfies a predetermined condition when a second event occurs;
A battery control device comprising: 2. The battery control device according to claim 1, wherein the setting unit sets the priority higher for a block having a higher degree of deterioration estimated by the first estimation unit. The first estimation unit estimates the degree of deterioration twice or more for each block of battery cells,
The battery control device according to claim 1 or 2, wherein the setting unit sets the priority based on two or more estimation results by the first estimation unit. 4. The battery control device according to claim 3, wherein the setting unit sets the priority higher for a block having a larger variation in the degree of deterioration estimated by the first estimation unit. 4. The setting unit according to claim 3, wherein the setting unit sets, to each of the blocks, a priority determined in advance according to the magnitude and variation of the degree of deterioration estimated by the first estimation unit. battery controller. A battery control method executed by a battery control device,
a first estimation step of estimating the degree of deterioration of each block of battery cells included in a battery pack mounted on a vehicle when a first event occurs;
a setting step of setting a priority to each of the blocks based on the estimation result of the first estimation step;
a second estimating step of estimating the degree of deterioration of each of the blocks whose priority set by the setting step satisfies a predetermined condition when a second event occurs;
A battery control method, comprising:

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